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Answer all questions 1. A 2 . A 3 A 4 A 2 5 6 Which row shows an SI base quantity with its correct unit? SI base quantity unit A charge coulomb B current ampere C potential difference volt D temperature degree Celsius A pendulum bob is held stationary by a horizontal force H. The three forces acting on the bob are shown in the diagram. 30° T H W The tension in the string of the pendulum is T. The weight of the pendulum bob is W. Which statement is correct? A H = T cos 30° B T = H sin 30° C W = T cos 30° D W = T sin 30° Space for working 3 7 The drag coefficient Cd is a number with no units. It is used to compare the drag on different cars at different speeds. It is given by the equation Cd = 2F ρv nA where F is the drag force on the car, ρ is the density of the air, A is the cross-sectional area of the car and v is the speed of the car. What is the value of n? A 8 1 B 2 C 3 D 4 A signal that repeats periodically is displayed on the screen of a cathode-ray oscilloscope. The screen has 1 cm squares and the time base is set at 2.00 ms cm–1. What is the frequency of this periodic signal? A 50 Hz Space for working B 100 Hz C 125 Hz D 200 Hz 4 9 Which estimate is realistic? A The kinetic energy of a bus travelling on an expressway is 30 000 J. B The power of a domestic light is 300 W. C The temperature of a hot oven is 300 K. D The volume of air in a car tyre is 0.03 m3. 10 Which unit is equivalent to the coulomb? A ampere per second B joule per volt C watt per ampere D watt per volt 11 Two forces of equal magnitude are represented by two coplanar vectors. One is directed eastwards and the other is directed northwards. What is the direction of a single force that will balance these two forces? A towards the north-east B towards the north-west C towards the south-east D towards the south-west Space for working 5 12 The spring constant k of a coiled wire spring is given by the equation 4 k = Gr 3 4nR where r is the radius of the wire, n is the number of turns of wire and R is the radius of each of the turns of wire. The quantity G depends on the material from which the wire is made. What is a suitable unit for G? A N m–2 B N m–1 C Nm D N m2 Space for working [Turn over 6 13 A 0.10 kg mass is taken to Mars and then weighed on a spring balance and on a lever balance. The acceleration due to gravity on Mars is 38% of its value on Earth. What are the readings on the two balances on Mars? (Assume that on Earth g = 10 m s–2.) spring balance / N lever balance / kg A 0.38 0.038 B 0.38 0.10 C 1.0 0.038 D 1.0 0.10 14 What is equivalent to the unit of electric field strength? J C m–1 A B N s A–1 C kg m s–3 A–1 D kg m3 s–3 A–1 15 The diagram shows the reading on an analogue ammeter. 5 10 milliamperes (mA) 0 15 Which digital ammeter reading is the same as the reading on the analogue ammeter? display units display reading A µA 1600 B µA 160 C mA D A Space for working 16.0 1.60 7 16 A steel wire is stretched in an experiment to determine the Young modulus for steel. The uncertainties in the measurements are given below. measurement uncertainty load on wire ±2% length of wire ±0.2% diameter of wire ±1.5% extension ±1% What is the percentage uncertainty in the Young modulus? A 1.3% Space for working B 1.8% C 4.7% D 6.2%